Best of both worlds: Setting up Wi-Fi for iOS on 2.4 and 5GHz

Each band has pros and cons, so here's how to use them together.

For a while, it seemed that Wi-Fi was becoming a victim of its own success. In many cities, there are numerous active Wi-Fi networks on those preciously few non-overlapping channels—that's in addition to microwaves, bluetooth, cordless phones, and baby monitors, which all share the 2.4GHz band.

But since about 2007, Apple has also built support for 802.11n Wi-Fi on the 5GHz band into its computers and Airport line of Wi-Fi base stations. Now, the iPhone 5 and the latest iPod touch also have that support. (The iPad has had it since day one.) So, how do you set up a Wi-Fi network that makes the most of this confluence of Wi-Fi bands?

Not created equal

First of all, it's important to realize that the two bands are created very differently. The 2.4GHz band suffers from lack of non-overlapping channels and interference from other devices. But the lower frequencies pass through walls and floors reasonably well. The 5GHz band on the other hand, has a much larger number of channels—and they don't overlap—but the higher frequencies have reduced range, even in open air. In addition to this, Apple only supports using two channels as a single, double-speed wide channel in the 5GHz band. If all else is equal, 5GHz is twice as fast as 2.4GHz.

Older base stations, such as the first and second generations of Apple's Airport Extreme (released in 2007), support either 2.4GHz or 5GHz operation, but not both at the same time. If you have one of those, you have to choose. In a small apartment with thin walls, 5GHz has enough reach, and you'll benefit from the extra speed and reduced interference. Especially when you let the base station select the channel, because that way, more channels are available. But in a big house away from interfering neighbors, 2.4GHz gives you better coverage further away from the base station. You may also need 2.4GHz for compatibility with older devices that don't support 5GHz operation.

But fortunately, with newer Wi-Fi base stations, it's no longer necessary to make that choice: they support simultaneous dual band, operating in both the 2.4 and 5GHz bands at the same time. There are two ways to do this: having a separate 2.4 and 5GHz networks, or having one network that spans both bands. In the first case, you tell the base station you want a different name (aka SSID) for the 5GHz band. This means you can manually select the 2.4GHz network or the 5GHz network as needed. The downside is that if you join the 5GHz network, and then move away from the base station, you'll remain connected to the 5GHz network and get spotty performance at distances that 2.4GHz handles just fine.

Enlarge/ Setting up a separate 5GHz network in the OS X Airport Utility

For most people, the best choice is to set up a network that does both 2.4GHz and 5GHz as a single network. This is what Apple's Airport Utility sets up for you if you don't tell it to use a separate 5GHz name. The benefit to this is that a single dual band network allows wireless devices that support both bands to switch to the band that has the best signal dynamically.

The iPhone 5 supports 72Mbps at 2.4 GHz, but 150Mbps at 5GHz. Most of Apple's computers have two antennas, so they can do 144Mbps at 2.4GHz and 300Mbps at 5GHz. My iPhone 5 quickly jumps from 5GHz to 2.4GHz when I walk down the stairs, but when I return to the living room, it typically takes a few minutes for it to switch back to 5GHz. And sometimes devices or computers get stuck on the 2.4GHz band just when you want to transfer some big files.

Adding to the family

Things get more interesting if you have multiple base stations. If you give each of these their own settings, wireless devices will try to hang on as long as they can before switching to a different one, and when they switch, all ongoing communication gets interrupted. But it doesn't have to be that way. You can have your own multi-base-station Wi-Fi network with seamless roaming, just like a campus or enterprise network, but using regular base stations such as Apple's Airport Extremes or Airport Expresses. (I didn't test with non-Apple equipment, but it should work the same way.)

iPhone 5 Speedtest results at 2.4GHz

Seamless roaming between base stations happens when four things are the same between those base stations: the network name (SSID), the security settings, the DHCP server, and the router. This is easily accomplished by hooking up the second base station to a LAN port of the first base station and setting the second one up with the same network name and the same WPA2 password. Then, tell the second base station that it should operate in "bridge mode," rather than perform NAT or DHCP.

It's also possible to set up a second base station as a wireless network extender to get more reach without putting in additional Ethernet wiring, but that requires extra wireless hops for each packet, so it reduces speed. In the wireless extender configuration, the second base station needs to be on the same channel as the first one. But if the second base station has a wired connection, it should have its own channel for best performance.

Don't forget that you can install the Airport Utility for iOS on your iPhone, iPod touch, or iPad, which lets you reconfigure your Airport base stations as well as monitor signal strength, connection speed, and the use of 2.4 vs 5GHz for all of their wireless clients, including iOS devices. Don't select a base station too fast, though, because then the list of wireless clients may not be shown.

Bonus tip: if you want to see what other Wi-Fi networks are active in your area, use the following command on your Mac:

I did some speed testing with an iPhone 5 and a fourth generation Airport Extreme base station. In normal Web browsing or e-mailing, there didn't seem to be a speed difference. On 2.4GHz, iTunes Wi-Fi sync topped out at 2.8 megabytes per second, while on 5GHz, this was about 50 percent faster at 4.3MB/s. However, I was able to transfer a file from the Air Sharing app using the Finder at no less than 10MB/s at 5GHz. The Speedtest app showed that the iPhone was able to saturate my 60Mbps Internet connection at 5GHz, but barely more than half that at 2.4GHz.

On the other hand, I find that when using a 5GHz-only network, dropping Wi-Fi connections and problems reestablishing a connection are much more common. In the dual band configuration, issues with 5GHz aren't an issue, because the wireless device simply falls back to 2.4GHz. Life is good with dual Wi-Fi bands.

Update: this story originally said 5GHz support was new in recent iPads, while in fact it was already present in the original iPad.

I have no idea how to say your name, but I very much enjoy your practical articles. I have stuff set up the same way and my experience mirrors yours. Good to know it's not because of PEBKAC.

I've had untold problems with some refurbed Netgear N300 wireless routers with dd-wrt. All the problems went away when I switched to a 5th gen Airport Extreme. Again refurbed, you can pick it up for $139 which is a great price if you have macs.

To be honest if you don't need an gigE switch or USB storage, the Airport Express will also do simultaneous dual band now and Airplay as well. Under $100. It has a 2x2 antenna array rather than a 3x3 of the Extreme but if your needs are small it'll do.

The Time Capsule is in the den, and reasonably far away from the living room where we do most of our browsing. I'd wired the house through a switch a while back to connect my media components (XBox, AppleTV and Windows Media Center) thinking that'd give me the best quality.

I was thinking I'd upgrade the switch soon … they're cheap, so if it gives any performance improvement it'd be worth it, I figure.

Other factors effect range. High frequencies are blocked more by obstacles, as you note. Noise (as from microwave ovens) limits range, as do the type of antennas, the transmitted power, and the sensitivity of receivers. In a particular WiFi device that may hurt the 5.6 GHz range more than that at 2.4 GHz, but that's a function of the device not the frequency. Doubling the bandwidth to cram more data through at 5.6 GHz, probably cuts the range too, but that's due to the amount of spectrum being used and not its frequency.

You can see that in the real world. JPL communicates with the furtherest man-made objects in existence, Voyager 1 and 2, on X-band, which is about 10 GHz. And all the stars whose light we see in the sky, including early galaxies over 10 billion light years away, are at light frequencies, which are even higher than microwave.

I once worked with a USAF missile tracking radar (FPS-16) that was C-band at frequencies very close to 5.6 GHz. We had no trouble bouncing a signal off the moon or tacking a copper-plated ping-pong ball inside a weather ballon out 200 miles. The effective reflective surface on the latter was probably about the size of a pencil eraser.

And yes, we were running multiple megawatts (up to 10) into out-sized dishes and had a maser front-end, but no one fretted about being C-band hurting our range. I also worked with a S-band radar (3 GHz), whose range was far less. That had nothing to do with the frequencies. It had everything to do with their differing designs. The antenna in the latter was far less directional.

In short, all this talk of 'higher frequency means shorter range' is an urban myth. Factors do effect range, but those factors are not purely a function of frequency. Any range limitations of open air 5.6 GHz are a function of hardware not basic physics.

I have my home set up pretty much exactly as described in the article.

I have 2 AEBSs and 1 Time Capsule (all 3 using 2.4 and 5 GHz with the same SSID and password). One of the AEBSs acts as router, connected using cat5e to the other AEBS, Time Capsule and an AirPort Express (all in bridge mode), as well as wired connection to TiVo box, Apple TV, AirPrint Printer and iMac by cat5e. The AEBS router is connected to a cable modem for 100Mb broadband. AirPlay (Zeppelin), iPhones, iPads, MacBook Airs, Wii and Kindles all roam and pick up the strongest signal wherever they are in the house.

All works nicely, though I sometimes wonder whether I'm causing my neighbours (terraced house) any problems as I'm using quite a few channels.

In short, all this talk of 'higher frequency means shorter range' is an urban myth. Factors do effect range, but those factors are not purely a function of frequency. Any range limitations of open air 5.6 GHz are a function of hardware not basic physics.

He'll correct me if I'm wrong, but I believe it would be ill-yitch or the i might be a long e so more like eel-yitch.

Actually I was never sure myself, as I'm named after the Russian composer Tchaikovsky but my parents didn't speak Russian at the time. (My mother tried to learn years later.)

But something like illyeets is fine.

About the 2.4 vs 5 GHz attenuation: I can't find anything definitive, but in general absorption in the atmosphere increases at higher microwave frequencies. However, the effect may still be small at 2.4 vs 5.1 - 5.8 GHz. On the third hand, this is the frequency that weather radar uses, so at the very least rain drops get in the way. Of course for deep space use only a tiny fraction of the path is affected by air.

Can anyone recommend software for Mac OS X, or Windows that will allow me to measure the interference level and/or the number of dropped packets for wifi testing? I've used InSSIDer in the past, which works well for measuring interference, but I've yet to come across anything useful for testing the number of packet resends.

I still can not believe the lack of support for 802.11n over 5GHz even tho it was added to the sepc in (i think) October 2009.

I moved all my devices to 5GHz when a friend gave me an Apple base station that supported it. Older one so it can not do 5.0 and 2.4 at the same time. I had a wireless sub with my soundbar I could not use a lot of the time because it completely overpowered my WiFi network. Causing slow speed or outright dropouts.

The iPad 1 which came out before the iPhone 4 supported 5GHz yet the the iPhone 4 did not. Was not till the iPhone 5 this was added. Pissed me off to no ned as I had to maintain two networks just to get the thing online. Oh wait... I still do because Sony went cheep as shit and the Vita does not support 5GHz (as well as WPA2 Enterprise, but that's for another rant).

Also note. Using anything less than gigabit to feed your 802.11n devices is just silly.

I still can not believe the lack of support for 802.11n over 5GHz even tho it was added to the sepc in (i think) October 2009....The iPad 1 which came out before the iPhone 4 supported 5GHz yet the the iPhone 4 did not. Was not till the iPhone 5 this was added. Pissed me off to no ned as I had to maintain two networks just to get the thing online. Oh wait... I still do because Sony went cheep as shit and the Vita does not support 5GHz (as well as WPA2 Enterprise, but that's for another rant).

2.4/5Ghz support requires an additional antenna over just 2.4 Ghz. This is why it shows up in the larger device (ipad1) but not in the smaller (iphone4,vita).

Dumb question: I have a newer Netgear -something- dual band router. Very nice except for its range. Anyone know of a good extender that works in bridge mode (as referred to in the article)? The house is hard wired for ethernet, so I'd like to be able to use the wired network to set the extender up on the other side of the house and continue to use the router as the gateway and such. All the extenders I am seeing are fairly cheap, but seem to use wifi only. So I'd have to leap frog them outward and add extra hops that I'd like to avoid.

The AirPort Utility is a really easy and elegant way to manage your wireless network. I recently helped someone who had a very large house that was only partially served by an AirPort Extreme expand the network using a pair of AirPort Express base stations via Ethernet. I used the AirPlay on one to hook up to the whole-home sound system so they can instantly and easily play music in the entire house from an iPhone or iTunes library. The whole process was quick and short of some software updates, everything just worked. Now you can easily roam inside the house on one SSID and be passed off between access points like a cell phone. Even for non-Mac people, I always recommend AirPort base stations because of the ease of use, and quality of service that they provide. Before I bought my Extreme, I tried a variety of wireless N routers and despite published specs, the performance varies wildly and is surprisingly poor if you try do do anything like transfer files between computers or stream media. AirPort was really the first base station that has lived up to my expectations.

One other thing I'd like to add which wasn't mentioned in the article is that MacBook Pro's are now equipped with 3x3:3 AirPort Card, and if you have an AirPort Extreme or Time Capsule, you can expect to see 450 Mbps link speed and USB 2.0 transfer speeds (~40MBps, 320Mbps) between a MBP near the station and another computer on GigE. For a wireless link, this is really quite impressive.

One more performance tip, AirPlay to an Apple TV can be slow to start sometimes when coming from an iOS device when both are connected via WiFi. The AppleTV will wait to buffer content before playing, especially HD video. If it is possible, connect the AppleTV via Ethernet to see a noticeable decrease in buffer times. This is due to the fact that on the same band, the router can only communicate with one device at a time. Although switching is extremely fast and happens thousands of time a second, a finite amount of data must be downloaded from the iOS device, cached, and then retransmitted to the AppleTV. Throughput must be shared between devices. When the AppleTV is on Ethernet, the base station can now have a more continuous WiFi stream from the iOS device and relay that info directly to the AppleTV via Ethernet without disrupting the download of data from the iOS device. This will really improve AirPlay experience if you can make this change.

In short, all this talk of 'higher frequency means shorter range' is an urban myth. Factors do effect range, but those factors are not purely a function of frequency. Any range limitations of open air 5.6 GHz are a function of hardware not basic physics.

I'm not sure what you read on Wikipedia, but frequency-dependent attenuation is actually not a myth at all. And range is certainly not an exclusive function of hardware. Attenuation of the 5GHz band is higher than 2.4GHz for several reasons outside of hardware (unless you're measuring them in a vacuum). Free space path loss, atmospheric attenuation, and fast and slow fading are all functions of frequency (among other things). It's not just JUST about hardware -- there are physics involved.

He'll correct me if I'm wrong, but I believe it would be ill-yitch or the i might be a long e so more like eel-yitch.

Actually I was never sure myself, as I'm named after the Russian composer Tchaikovsky but my parents didn't speak Russian at the time. (My mother tried to learn years later.)

But something like illyeets is fine.

Reminds me of how most people call Moog synthesizers Moog (like a cow says), but others say it is Mogue (rhymes w/rogue). Bob Moog was even quoted as saying that either is technically correct b/c some people in his family say it one way and some the other. It's always fun to remind people of that after they freak out on you for saying it with the 'oo' instead of the 'oh'

The problem with using the same SSID for both 2.4 GHz and 5 GHz networks, is then there's no way to force the iPad/iPhone on to the correct network and really the user has no idea what network the device is on.

My set up at home is to have 2 networks (on one router) with different SSIDs. The 2.4 GHz network tends to have interference, but has a farther range. The 5 GHz network has less interference, but has problems reaching all the areas in my house. I've associated my iPad 2 with both networks so it can switch when it feels like it. From my testing I've found, that at least on my iPad 2 (iOS 6.0.1), once it selects a 2.4 GHz, it will stay on that network, even if I go back in range of the 5 GHz one. It also tends to prefer the 2.4 GHz network when I come home. As such I frequently have to go in and force it back on to the 5 GHz network.

If I used the same SSID for both networks, I'd never have any idea if my iPad 2 is connecting to the 2.4 GHz or 5 GHz network and there would be no way to force the iPad back on the 5 GHz network.

Frequency can affect the number of destructive interferences of information symbol transmissions. It's called multi-path propagation fading. You can bounce signals off of dust at a certain point in the air. It's a problem inherent in frequency of a signal.

Thanks for the article. I'm about to upgrade my G router to a new 5GHz N model and was considering the Apple product. I actually bought the Linksys EA4500 and got caught up in that acess-from-the-internet-only crap so took it back.

BTW, Apple secretly introduced 5GHz N support in the late 2006 model MacBook Pro. I know because I had/have it. Remember the controversy about Apple charging 5 bucks for it?

Seamless roaming between base stations happens when four things are the same between those base stations...

Oh how i wish this were true. I purchased identical Asus N routers a couple years ago, and couldn't get any sort of handoff to happen. Worse, because they were named the same, I couldn't even manually select the one I was closest to.

I finally changed the SSID of the "bridge" unit, so now I just deal with the hassle of picking the network depending on the end of the house I'm in. /firstworldproblems

I don't have any apple gear in my house, but knowing this is relatively simple with the Airport may have made my next router decision for me.

Anyone else have a handoff setup working (easily) with other out of the box consumer routers? Is the airport the way to go here?

Edit to ask: and what about the channel? Should they be the same on all routers (for sameness' sake), or different to avoid interence?

Dumb question: I have a newer Netgear -something- dual band router. Very nice except for its range. Anyone know of a good extender that works in bridge mode (as referred to in the article)? The house is hard wired for ethernet, so I'd like to be able to use the wired network to set the extender up on the other side of the house and continue to use the router as the gateway and such. All the extenders I am seeing are fairly cheap, but seem to use wifi only. So I'd have to leap frog them outward and add extra hops that I'd like to avoid.

Thanks!

Although link speed will not be N, you can pick up a WRT-54G almost anywhere second hand and upload a DD-WRT firmware. It is very easy to do and there are step by step instructions available for that specific model. From there, enabling bridge mode is again following simple instructions and a few clicks. Micro firmwares are usually the best because they only include the basic router enhancements and leave out the extra stuff you don't need.

Dumb question: I have a newer Netgear -something- dual band router. Very nice except for its range. Anyone know of a good extender that works in bridge mode (as referred to in the article)? The house is hard wired for ethernet, so I'd like to be able to use the wired network to set the extender up on the other side of the house and continue to use the router as the gateway and such. All the extenders I am seeing are fairly cheap, but seem to use wifi only. So I'd have to leap frog them outward and add extra hops that I'd like to avoid.

Thanks!

Any wireless access point should be able to do this, though you may want to find a similar Netgear model to ensure interoperability. Add the access point to any of your live ethernet jacks in the house. Log in to it through the web interface and set its IP to be part of your local subnet, then configure the wireless settings to match the existing wireless network's SSID and WPA security level, as described in the article. The access point should not be set up with DHCP.

Good luck!

(edit - the response above mine is a good one if you're somewhat technically inclined. DD-WRT is great and I use it at home and love it, but it can be complicated to install if you're not very tech savvy.)

Seamless roaming between base stations happens when four things are the same between those base stations...

Oh how i wish this were true. I purchased identical Asus N routers a couple years ago, and couldn't get any sort of handoff to happen. Worse, because they were named the same, I couldn't even manually select the one I was closest to.

I finally changed the SSID of the "bridge" unit, so now I just deal with the hassle of picking the network depending on the end of the house I'm in. /firstworldproblems

I don't have any apple gear in my house, but knowing this is relatively simple with the Airport may have made my next router decision for me.

Anyone else have a handoff setup working (easily) with other out of the box consumer routers? Is the airport the way to go here?

Edit to ask: and what about the channel? Should they be the same on all routers (for sameness' sake), or different to avoid interence?

Channel selection should be varied between the base stations on the same network unless everything else around you is extremely congested. On a PC or Mac with Java installed, search for "Meraki Tools WiFi Stumbler" and this will bring you to a great, free web-app so you can visualize the amount of network traffic on 2.4 and 5GHz if you have a dual band WiFi card in your computer. Hand-off between base stations is built-into the 802.11 standard and is *supposed* to work easily, but like the author said, you have to have all of your settings correct. Open source firmwares, if available for your model usually implement a base station/repeater setup well. In my experience of setting up lots of WiFi networks for education research, work and home, the stock firmwares are usually pitiful pieces of software that are marginally functional. Open source is truly a better solution, more thoroughly debugged and better implemented.

Seamless roaming between base stations happens when four things are the same between those base stations...

Oh how i wish this were true. I purchased identical Asus N routers a couple years ago, and couldn't get any sort of handoff to happen. Worse, because they were named the same, I couldn't even manually select the one I was closest to.

I finally changed the SSID of the "bridge" unit, so now I just deal with the hassle of picking the network depending on the end of the house I'm in. /firstworldproblems

I don't have any apple gear in my house, but knowing this is relatively simple with the Airport may have made my next router decision for me.

Anyone else have a handoff setup working (easily) with other out of the box consumer routers? Is the airport the way to go here?

Edit to ask: and what about the channel? Should they be the same on all routers (for sameness' sake), or different to avoid interence?

Access Point selection is up to the client, it has nothing to do with the access points configuration. If they are sharing the same SSID, then the client will decide with access point to talk to, and it will decide when to switch. Typically the switch happens when a client decides that the other station has better radio characteristics than the currently active station for some period of time.

In order to make a smooth transition, the access points should be connected to the same broadcast domain with only a single DHCP server, router, etc. in essence the IP configuration of the client must be valid on the 2nd access point as well.

If your access point radios interfere with each other (ie, they are within range of each other) then they should be on different channels (non-overlapping). Nowadays, it's better to just set them to automatic so they'll always pick the best channel available.

Seamless roaming between base stations happens when four things are the same between those base stations...

Oh how i wish this were true. I purchased identical Asus N routers a couple years ago, and couldn't get any sort of handoff to happen. Worse, because they were named the same, I couldn't even manually select the one I was closest to.

You wouldn't be using Android devices by any chance? Wifi roaming does not work on stock Android, see issue 12649. (Apparently some devices have manufacturer-specific workarounds.)

I honestly don't understand the purpose of 5Ghz. I've set it up on my Airport Extreme briefly, and found that unless I was within about five feet of the router it was an order of magnitude slower than 2.4Ghz. We're talking slower than 802.11b speeds. Why would anyone use this frequency when the performance is so bad?

I plug my old routers into my wired LAN when I get new ones, my latest is a Netgear D600 which has 2.4 and 5 WiFi under two names, one of the old 2.4 routers shares the name with the D600, then the lodes router is a 2.4 with a different name.

What I have is 3 network names running off three routers across 2 bands.

Iljitsch van Beijnum / Iljitsch is a contributing writer at Ars Technica, where he contributes articles about network protocols as well as Apple topics. He is currently finishing his Ph.D work at the telematics department at Universidad Carlos III de Madrid (UC3M) in Spain.